This invention relates to a band-gap reference-voltage arrangement comprising
a differential amplifier in MOS technology having two inputs and one output, PA1 a first bipolar transistor whose base-emitter path is arranged between one input of the differential amplifier and a specific junction point and whose emitter-collector path is arranged in a first current path for carrying a first current, PA1 a second bipolar transistor whose base-emitter path is in series with a resistor and is arranged between the other input of the differential amplifier and said junction point and whose emitter-collector path is arranged in a second current path for carrying a second current, PA1 a series arrangement of a second and a third resistor connected between a supply voltage terminal and an output terminal for taking off a reference-voltage, the junction point between the second and the third resistor being coupled to the base of the second transistor, PA1 the output of the differential amplifier being coupled to the output terminal of the arrangment, and PA1 means for supplying said first and second currents through said first and second current paths. PA1 the common-mode input voltage at the inputs of the MOS differential amplifier is frequently such that the MOS transistors in this amplifier have to operate in their triode region, which may result in an unbalance in the differential amplifier and a loss of gain so that the performance of the entire band-gap reference-voltage arrangement deteriorates, PA1 the required chip area for the resistors in the arrangement is generally found to be considerable, PA1 the MOS differential amplifier is afflicted with an offset caused by mismatching of components in the arrangement.
Such a band-gap reference-voltage arrangement is described, for example, in U.S. Pat. Nos. 4,380,706 and 4,287,439, and in PCT application WO 81/02348. For an explanation of the operation of these known circuit arrangements reference is made to the literature cited and to general articles, such as the article "Band-gap Voltage Reference Sources CMOS Technology", Electronics Letters, 7 Jan., 1982, Vol. 18, no. 1, pages 24/25.
Depending on the specific topology, these known circuit arrangements have one or more of the following drawbacks: